Diagnosis
What causes autism?
No one is sure yet. Researchers are working to understand the
etiology of autism, but so far nothing has been consistent
across all cases. Human physiology is a long chain of intricate events,
starting with genetic code and ending in the outward appearances and
personalities we see everyday. Along the way, molecules are combined
and taken apart, cells are built, proteins synthesized, hormones regulated,
neural function promoted, and on down the line. We know that genetics
play a significant role; unfortunately no genes have been explicitly implicated.
It is also known that exposure to certain environmental toxins such
as thalidomide is associated with a later diagnosis of autism. We
cannot rule out the possibility that other toxins may again
cause similar symptoms.
Diagnosis
With the documented benefits of early intervention for learners
with an autism spectrum disorder (ASD), the earlier the diagnosis
can be made, the better. As there is no genetic or medical test for
ASDs, clinicians rely on behavioral observation, generally quantified
through the use of a standardized diagnostic scale, to arrive
at the diagnosis. In general, diagnosis is a two step process: 1) screening,
and 2) a comprehensive diagnostic evaluation.
Screening
Most “well child” check-ups include a developmental screening. Parent
observations, impressions and concerns are an essential part of the screening
and may be supported by such “documentary” information
as family videos and baby albums. Once concerns are voiced, the
parents may be asked to complete any of a number of standardized screening
instruments such as the Checklist for Autism in Toddlers (CHAT) or the
Screening Tool for Autism in Two-Year-Olds (STAT). If following
the screening process there continues to be concern, a comprehensive diagnostic
evaluation is indicated.
Comprehensive Diagnostic Evaluation
In order to rule in or rule out an ASD diagnosis a comprehensive
diagnostic evaluation is required. This evaluation is generally
done by a team of trained professionals that may include a psychologist,
a neurologist, a psychiatrist, a speech and language pathologist, or
other relevant professional (e.g., occupational therapist). Given
the complexity often associated with ASDs, special attention during
the evaluation should be paid to neurological testing along
with in-depth cognitive and language testing. Other tests may
include a hearing evaluation and a lead screening. Lastly, assessments
specifically designed to reliably identify presence of an ASD are used. Primary
among these is the Autism Diagnostic Observation Schedule (ADOS) but
the Autism Diagnostic Interview-Revised (ADI-R) and the Childhood Autism
Rating Scale (CARS) are also commonly used.
What next?
Hearing the diagnosis of autism is an overwhelming and potentially
devastating blow to families. However, the time of diagnosis is
also the time to stay focused and ask questions. In addition to
providing the diagnosis, members of the evaluation team are a family’s
best, most immediate source for information, recommendations, direction
and referrals. It is important that families not leave this meeting
without the names and numbers of trained professionals, programs and
related resources in their geographic area. Early diagnosis can
lead to effective early intervention which can lead to significant gains
for the newly diagnosed individual but only if the family now knows
where, and to whom, to turn.
From Autism Spectrum Disorders: Pervasive Developmental
Disorders (2004).
National Institutes of Mental Health.
Available online at
http://www.nimh.nih.gov/publicat/autism.cfm
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